I recently bought a set of Mullard 6dj8's and was able to get some RCA Oa3's and Oc2's at a good price. The RCA oC2's look identical to the Raytheons that were stock but the OA3's are different than the GE's, they are straight sided. The sound is a bit thinner than before. Is this a symptom of new regulators? Will , are you running RCA and can give you gime me any feedback. The mullards may need some more time also. I hate new tubes. My cheap jj 6922's actually do not sound bake after a bunch of hours.

I agree about the burn in. But the quest keeps me in it. I get so close, and then try something new and realize there is more to flesh out! I particularly enjoy tubes and finding different ways of arriving at fresh synergy with them.

One thing is for sure though. As I get closer to my sense of balance in the system, each new break in is less painful, but it always hurts! Have you tried the esoteric CD or Sheffield Drum Tracks to get some of that burnin done while you are away.

And of course this is all based on my system and how the parts make a whole, but I hope I can help with general comments.

Though I don't have any RCA OA3 straights, straight sided regulators I have tried are generally more open, spacious and detailed compared to the earlier 50/60s STs (coke bottle). Also it seems easier to get OC3s than OB3 and OA3 straights, so there can be the more open effect from the higher voltage Regs as well. But the Amperex OA3 straights I have fit the pattern. This is a generalization though, I do have some 80s Sylvania OA3 STs that are quite open and spacious.

If the balance is off with the a given tube set, the straight sides I have can be too open/bright. But with the right counterparts, I think they can sound great. I have not tried them all by any means, and of course there is variation within, just like with STs of the same type but with construction and date variation.

On the other hand, the early STs seem more rich and warm, and if the balance is off with the other tubes, veiled and dense.

Regs, like the rest, do take time to show their deeper nature. When getting right down to it, I don't think any of my tubes except pulls/used have sounded close to their best for at least 50 hrs, and some 150 or more to really show their subtle character. Regulators do seem to come around on the quick side though.

I found that I preferred OC2 RCAs over Raytheons, the RCAs being subtly more open and transparent. This is a taste thing, but worth looking at in your present situation.

I have not heard the JJ 6922, but my experience with the input types, aside from whether the individual tube tends to "warmth" or transparency, I find the 6922s to be more solid and clear edged than 6DJ8s and 7DJ8s. The DJ8s seem generally more textured...more apparent micro detail, a quality I prefer in general. So I use other tubes to balance the DJ8s sometimes subtle, sometimes very notable tendency to a more open textured sound, especially, the 7DJ8s.

Anyway, if the JJs are warmish and solid sounding, like many 6922s, it is possible that the Mullards could be contributing slightly to the thin thing you are hearing. And if the Mullards are new, they will definitely take a while to come out fully. I buy pulls whenever I can to avoid the big prices and the burnin time. I got some really nice Mullard 6DJ8s from partsconnexion, said to be over 90% for $70 or so.

So I would say that each of your three new tubes could be contributing to the slightly "thin" quality you are hearing.

But then we have the bass and treble knobs, and though I tend to have a range I like, especially with the bass knobs, I need to adjust them with many tube shifts. I will use them anywhere in the range depending on the tube set, but usually between 9 and 2 o'clock.

I had been using JJ 6CA7s for my power tubes for a while, and they are really good sounding tubes...solid, detailed and "tubey" but a darkish and veiled with the wrong set. So I tend to use brighter, more detailed inputs and regs with them. I had some Sylvania OA3s, RCA OC2s, Zaerex/Philips 7DJ8s (all brightish) with the JJs and liked the balance and sound a lot. Then I decided to sub in my cryoed Shuguang EL34s, which are especially open and detailed with a seductive dynamic quality and deep quiet between the notes. It hurt, the set was so bright, so I had to move the treble way back from what I had, which helped, but still too edgy overall. Then I stuck in some 50s Tungsol OB3 STs that are sweetly warm and textured, and all was beautiful, the treble knobs going almost back to where they had been with the darker, but great sounding (with the right synergy) JJ 6CA7s.

Long story short. I wonder if you can get where you like the sound by playing with the balance of the bass and treble knobs. Maybe even some slight speaker movement, or cable rolling??? If so, all three new tubes will improve as they break in and you could get it all done at once. However you do it though, once broken in, then at least you will know the true character of the new tubes and be able to use them better toward system synergy that you like.

I love to roll tubes for the occasional lift from varying one great signature synergy to another, exciting the musical experience and at times finding previously unknown territory. With my weakness for tubes, I do have a lot of choices though!

Will, I bought all the tubes from Kuray. I am listening now and I have adjusted the pots on the back and I think the Mullards are a little new and for lack of better description 'constipated'. Not ready to let go of the notes. Not terrible, not bad sounding in any way just holding back. I have been following some talk about the Gold Lion KT77 and may try them. I talked to Steve today and forgot to ask if the KT77 is capable of working with the Hazen Grid Mod. There is also some talk about the Gold Lion 6922's sounding pretty good and some dealers selling them for $36.00. I did order a few pull Amperex Orange Globe's form Kuray also but one bit the dust on second turn on- he is sending another, no problem. For there price the JJ 34 sound interesting but the Tung Sols are way better here compared to the Re-Issue Mullards and I am a little hesitant to put another warmish sounding tube.Walt

I get that about warmish power tubes, especially if you don't have brightish ones to mix with them. I did not like the JJ 6CA7s until I got them with the right mix, then I could hear the thing I imagine the advocates for the tube are hearing. For me, they were a particularly painful burnin too taking a really long time. I have not compared them to the Tungsols.

I bet you are right on those Mullard 6DJ8s from Koray being brand new and I bet they will come out after a while. Constipated is not a descriptor I would associate with the Mullards I have, so hopefully they will sound good. From his description, they sound really interesting. Please keep us informed.

Too bad about the Orange globes. I will be interested if the replacements suit your tastes.

It is my understanding that the Hazen Grid mod on the Torii works only with EL34s and 6CA7s and that other tubes work in the amp, but will not benefit from the mod.

I believe Steve considers the Hazen Grid Mod so effective with EL34 types as to rule out the potential benefit from the other power tubes in the Torii. So I have never gone there, but if I had some KT-77s on hand, I would surely have to check them out!